Susan Wagener on sat 8 nov 97
My first shipment of glaze chemicals have arrived and I'm anxious to get
started with this new venture of making my own glazes. I would like to
have this one statement I wrote down from a glaze making class verified by
those of you with more experience in this area before I do this and make a
mess of my kiln and pots!
Here is the statement as I wrote it down:
You can reduce a ^9 - ^10 glaze recipe to ^6 by doing the following:
Drop Feldspar, Soda or Potash Feldspar
Add exact amount of Nephline Synate plus 10% Gerstley Borate or Colmonite
Has anyone successfully done this? I only glaze fire to ^6 and a lot of
the recipes I've found are for the ^9 - ^10 firing range. I don't mind
experimenting but I can't afford to have glazes running all over my brand
new kiln. Somehow I don't think my husband would understand if that
happened. He already thinks I'm going to kill us all off with these
chemicals sitting in the garage! So I am measuring twice so I can cut once
(in his woodworking terms)!
Thank you in advance for your advice!
A little on the nervous side about starting this new process....
Susan Wagener
Puffin Pottery
Bloomington, IN
50 degrees and sunny today!
Paul Lewing on sun 9 nov 97
Susan,
I've never heard of or used the particular formula you mention for
taking a ^10 glaze down to ^6. It very well might work. I have had
success sometimes with the "throw in a frit till it melts" method, and
I've also successfully taken recipes down that far by adding lithium
carbonate.
You may get glazes that flux at the lower temperature, but you're not
likely to get exactly the same surface quality or color response. You
are, after all, altering the flux balane when you do this, and you're
probably also altering the Si:Al ratio. Certainly you are altering
the SiB:Al ratio by adding GB or Colemanite.
Some ^10 recipes just won't go down that far. I made that temperature
switch about 11 years ago, and I've come to like it better, but it
took at least three years of constant testing before I had glazes I
thought were as interesting as the higher temperature ones.
Good luck,
Paul Lewing, Seattle
Ron Roy on mon 10 nov 97
Hi Susan,
Best way to do this is with glaze calculation software.
I suggest you design some test tiles that will catch any running.
I would avoid Neph Sy because it will make at least some of your glazes
settle out in the bucket - depends on how much you use.
I would also avoid too much gerstley borate - Frit 3134 is a good frit to
use because it has no alumina - that way you can have more clay in the
bucket and also use G200 or Custer instead of Neph Sy.
OK I know - how much is too much GB. Depends how paranoid you are about
it's variability and tendency to flocculate a glaze. On the other hand it
does help to keep glazes in suspension, form a tough surface on the dry
glaze and is cheaper than frit. - I'm guessing, making it up, taking a wild
stab - 5 to 10 percent - tops. If you need more boron use 3134.
If you need some help here send me a glaze you want lowered and I will show
you what I mean. Tell me what kind of clay you will be using and the kind
of spar you have as well.
Don't expect the cone 6 glazes to look like the cone 10 glazes.
>----------------------------Original message----------------------------
>My first shipment of glaze chemicals have arrived and I'm anxious to get
>started with this new venture of making my own glazes. I would like to
>have this one statement I wrote down from a glaze making class verified by
>those of you with more experience in this area before I do this and make a
>mess of my kiln and pots!
>
>Here is the statement as I wrote it down:
>
> You can reduce a ^9 - ^10 glaze recipe to ^6 by doing the following:
>
> Drop Feldspar, Soda or Potash Feldspar
> Add exact amount of Nephline Synate plus 10% Gerstley Borate or
>Colmonite
>
>Has anyone successfully done this? I only glaze fire to ^6 and a lot of
>the recipes I've found are for the ^9 - ^10 firing range. I don't mind
>experimenting but I can't afford to have glazes running all over my brand
>new kiln. Somehow I don't think my husband would understand if that
>happened. He already thinks I'm going to kill us all off with these
>chemicals sitting in the garage! So I am measuring twice so I can cut once
>(in his woodworking terms)!
>
>Thank you in advance for your advice!
>
>A little on the nervous side about starting this new process....
>
>Susan Wagener
>Puffin Pottery
>Bloomington, IN
>
>50 degrees and sunny today!
Ron Roy
93 Pegasus Trail
Scarborough,Canada
M1G 3N8
Evenings, call 416 439 2621
Fax, 416 438 7849
Studio: 416-752-7862.
Email ronroy@astral.magic.ca
Home page http://digitalfire.com/education/people/ronroy.htm
Greg Lamont on tue 11 nov 97
Paul,
Since acquiring my own electric kiln about a year ago, I've been working on
finding a palette of ^5-6 oxidation glazes that I can live with. It's
especially difficult since I've become used to the looks of ^9-10 reduction
glazes used at the university I attend. My teacher is allowing me to
research this temp. range and atmosphere as long as I'm willing to do it on
my own. The necessity to learn some glaze chemistry and calculation in
order to do this has been a valuable learning experience, but I was
beginning to get a little frustrated at the
length of the learning curve until I read the last sentence of your post.
Now I feel better. Thanks!
Regards,
Greg
in Ames, Iowa, where winter seems to have settled in.
At 11:36 PM 11/9/97 EST, you wrote:
>----------------------------Original message----------------------------
>Susan,
>I've never heard of or used the particular formula you mention for
>taking a ^10 glaze down to ^6. It very well might work. I have had
>success sometimes with the "throw in a frit till it melts" method, and
>I've also successfully taken recipes down that far by adding lithium
>carbonate.
>You may get glazes that flux at the lower temperature, but you're not
>likely to get exactly the same surface quality or color response. You
>are, after all, altering the flux balane when you do this, and you're
>probably also altering the Si:Al ratio. Certainly you are altering
>the SiB:Al ratio by adding GB or Colemanite.
>Some ^10 recipes just won't go down that far. I made that temperature
>switch about 11 years ago, and I've come to like it better, but it
>took at least three years of constant testing before I had glazes I
>thought were as interesting as the higher temperature ones.
>
>Good luck,
>Paul Lewing, Seattle
>
Ron or Sue Corl on thu 13 nov 97
I am sure that some of ya'll may disagree but I found the Robin Hopper
book 'The Glaze Spectrum' a great resource. It was easy to understand if
you have just a little knowledge of glazes. What little experimenting
that I have done since I have red the book has turned out great. I even
got a "fire engine red" at cone 10 reduction on a rainy day (but thats
another thread). I have not been able to duplicate it but that one
firing was worth the cost of the book!
Ron
Big Baby Head Studio
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